Study of Silicon Nitride Inner Spacer Formation in Process of Gate-all-around Nano-Transistors

• Published in: Nanomaterials (Basel, Switzerland) Vol. 10; no. 4; p. 793
• Main Authors: Li, Junjie, Li, Yongliang, Zhou, Na, Xiong, Wenjuan, Wang, Guilei, Zhang, Qingzhu, Du, Anyan, Gao, Jianfeng, Kong, Zhenzhen, Lin, Hongxiao, Xiang, Jinjuan, Li, Chen, Yin, Xiaogen, Wang, Xiaolei, Yang, Hong, Ma, Xueli, Han, Jianghao, Zhang, Jing, Hu, Tairan, Cao, Zhe, Yang, Tao, Li, Junfeng, Yin, Huaxiang, Zhu, Huilong, Luo, Jun, Wang, Wenwu, Radamson, Henry H
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 20.04.2020; MDPI
• Subjects: Anisotropy; Chemical vapor deposition; Etching; Etching equipment; Field effect transistor; Gas mixtures; Gate-all-around (GAA); High anisotropy; High etch selectivity; Inductively coupled plasma; Inner spacer; Investigations; Low pressure; Morphology; Nanosheet; Nanostructure manufacture; Nanotechnology; Nanowire; Nanowires; Plasma etching; Selectivity; Semiconductor devices; Silicon; Silicon dioxide; Silicon nitride; Silicon wafers; Thin films; Transistors; United States > US; gate-all-around (GAA); high etch selectivity; inner spacer; nanostructure manufacture; high anisotropy; field effect transistor; nanosheet; nanowire
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano10040793

Stacked SiGe/Si structures are widely used as the units for gate-all-around nanowire transistors (GAA NWTs) which are a promising candidate beyond fin field effective transistors (FinFETs) technologies in near future. These structures deal with a several challenges brought by the shrinking of device dimensions. The preparation of inner spacers is one of the most critical processes for GAA nano-scale transistors. This study focuses on two key processes: inner spacer film conformal deposition and accurate etching. The results show that low pressure chemical vapor deposition (LPCVD) silicon nitride has a good film filling effect; a precise and controllable silicon nitride inner spacer structure is prepared by using an inductively coupled plasma (ICP) tool and a new gas mixtures of CH F /CH /O /Ar. Silicon nitride inner spacer etch has a high etch selectivity ratio, exceeding 100:1 to Si and more than 30:1 to SiO . High anisotropy with an excellent vertical/lateral etch ratio exceeding 80:1 is successfully demonstrated. It also provides a solution to the key process challenges of nano-transistors beyond 5 nm node.